Bosch Rexroth A2FO A4FO fixed-displacement hydraulic pump for the Schwing Stetter Equipment 10068797 10089049 10174306 10186729 10196520 98316493

Both the A2FO and A4FO are fixed-displacement axial piston pumps based on the bent-axis principle, specifically designed for open-circuit hydraulic systems. "Fixed-displacement" means that the volume of fluid delivered per revolution of the pump shaft remains constant; the flow rate varies only with changes in the drive speed.

A2FO in brief

The A2FO is the long-established workhorse of the family. Key traits:

Bent-axis rotary group with tapered roller bearings

Wide size range, from small units up to large-displacement versions

Nominal pressure around 400 bar, with higher peak ratings (confirm per size)

Strong tolerance for shock loads and contaminated environments

Broad availability and a large installed base worldwide

A4FO in brief

The A4FO is the newer-generation design for open circuits. Key traits:

Same bent-axis concept, with a more compact, refined housing

Typically 400 bar nominal pressure, with higher peak ratings

Improved efficiency and noise behavior in many sizes

Several mounting and port options, including SAE and ISO styles

Why bent-axis matters on a construction machine

Bent-axis designs tolerate shock loads and fluctuating speeds well. Concrete machinery sees both constantly: a loaded drum starting up, a pump stroke reversing, a plant motor cycling. That durability is why bent-axis pumps are so common in mobile and heavy industrial work.

Where These Pumps Fit in Schwing Stetter Equipment

Schwing Stetter builds concrete mixers, batching plants, and concrete pumping equipment. Fixed-displacement pumps like the A2FO and A4FO usually serve auxiliary and constant-flow circuits rather than the main variable-flow drive.

Typical applications

Agitator and mixer drives where a steady flow is enough

Cooling and oil-circulation circuits (fan drives, oil coolers)

Water or additive pump drives on mixer trucks

Batching plant conveyors, screws, and gates

Auxiliary functions on concrete pumps, such as outrigger or boom support circuits (depending on the machine)

Example 1: Cooling circuit on a concrete pump

A truck-mounted concrete pump runs its main hydraulic circuit at high pressure for hours in summer heat. A fixed-displacement pump feeding the cooler fan motor gives constant flow with a simple, reliable setup. No complex control is needed, and fewer components mean fewer failure points on site.

Example 2: Agitator circuit at a batching plant

An agitator needs steady torque and speed. A fixed pump sized to the motor's flow requirement does the job. If the pump wears and internal leakage rises, the agitator slows. That is often the first symptom operators notice.

Common Problems and Practical Fixes

Pump noise or whining

Most often cavitation or aeration on the suction side. Check the suction filter, oil level, hose condition, and fittings for air ingress.

Loss of speed or power

Usually internal wear. Measure case drain flow. A high reading compared with the datasheet or a known-good unit points to worn pistons or a worn port plate.

Overheating

Look at the cooler, oil level, relief valve setting, and internal leakage. A worn pump converts wasted flow into heat.

Early failure

Most early failures trace back to contamination, dry start-up, or wrong oil. In concrete environments, cement dust and water ingress are constant threats, so breathers and filtration deserve extra attention.

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Q1: How do I know the pump is worn?

A1: Falling actuator speed, rising oil temperature, and increased case drain flow are the classic signs. Case drain measurement is the most reliable field test.

Q2: How long does an A2FO or A4FO last?

A2: With clean oil, correct installation, and sensible duty, many run for many thousands of hours. Contamination is the biggest life-shortener.

Q3: What is the price and delivery time of the Rexroth A2FO/A4FO pump for Schwing Stetter Equipment?

A3: The specific price and delivery time will depend on the equipment model or specific product model you provide.

Q4:How to purchase a Rexroth A2FO/A4FO pump for Schwing Stetter Equipment?

A4:You can visit https://www.baolilaihydraulic.com/contact/ to contact us and purchase our products through various methods.